Thank you for the report, fixed for 2.0.2.
And the migration exists because in Factorio 2.0 there's lots of API changes, so any mod with runtime scripting and storing things in 'sotrage' (formerly known as 'global') has a good chance of needing to migrate. Of course it depends on the mod. In QAI's case the 2 changes to the API which required a migration file are the fact that 'rendering' objects are no longer referred to by an id, they are now full LuaRenderingObjects, and the fact that 'rendering.draw_polygon' expects a different format for its vertices (and QAI has those cached in 'storage').
Another API change that technically needs migration in QAI is the new directions in 2.0. There's 16 instead of 8 now. So any direction value in 'storage' would need to be migrated, however in QAI I was luckily able to pretty much ignore this change as there's a generic 'switch_to_idle_and_back' function in QAI which gets called 'on_configuration_changed' which completely resets a given player's state and repopulates it with new values - including new and correct direction values.